A new putative plasmodesmata-associated protein, At1g19190, in Arabidopsis

摘要: 4-α-Glucanotransferase (4-α-GTase, EC 2.4.1.25) simultaneously catalyzes amylose molecular intra- and inter- transglycosylation to produce cyclodextrins (CDs) with DP of 9 several hundreds. In this study, the 4-α-glucanotransferase (4-α-GTase) from recombinant Escherichia coli DH-5α was proved large ring (LR-CDs) polymer degree 20 47. To maximize 4-α-GTase productivity effect, conditions for production were initially carried out in shake flasks investigate effects carbon sources, nitrogen trace elements, inoculum size, liquid volume, pH temperature. The results showed that increase biomass ( E. growth) sync. Glycerol g/l medium, as best source, provided high 102.55 U/ml 4-α-GTase, which 0.59-fold compared minimal medium. Organic source enhanced more enzyme activity than inorganic source; beef extract identified most effective enhancement. order get highest activity, optimum incubation initial fermentation broth at 7.0, culture temperature 37°C, size 2.0% volume 50 ml 250 Erlenmeyer. Under these conditions, 4-α-Gtase 5 L fermenter reached 198.7 U/ml. Key words : High cell density, 4-α-glucanotransferase, coli, large-ring cyclodextrin,